U.S. patent application number 17/110865 was filed with the patent office on 2022-06-09 for apparatus and method for rotor temperature measurement.
The applicant listed for this patent is GM Global Technology Operations LLC. Invention is credited to Jeremie Dernotte, Lei Hao, Scott E. Parrish, Wei Zeng.
Application Number | 20220181950 17/110865 |
Document ID | / |
Family ID | 1000005301229 |
Filed Date | 2022-06-09 |
United States Patent
Application |
20220181950 |
Kind Code |
A1 |
Zeng; Wei ; et al. |
June 9, 2022 |
APPARATUS AND METHOD FOR ROTOR TEMPERATURE MEASUREMENT
Abstract
An apparatus for automobile vehicle rotor temperature
measurement includes a motor having a rotor. A stator has the rotor
positioned within the stator. An aperture extends through the
stator. A sensor is positioned in alignment with the aperture
sensing a temperature of at least a surface of the rotor.
Inventors: |
Zeng; Wei; (Oakland
Township, MI) ; Parrish; Scott E.; (Farmington Hills,
MI) ; Hao; Lei; (Troy, MI) ; Dernotte;
Jeremie; (Shelby Twp, MI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
GM Global Technology Operations LLC |
Detroit |
MI |
US |
|
|
Family ID: |
1000005301229 |
Appl. No.: |
17/110865 |
Filed: |
December 3, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G01J 5/0022 20130101;
H02K 11/25 20160101 |
International
Class: |
H02K 11/25 20060101
H02K011/25; G01J 5/00 20060101 G01J005/00 |
Claims
1. An apparatus for automobile vehicle rotor temperature
measurement, comprising: a motor having a rotor; a stator with the
rotor positioned within the stator; a first aperture or opening
extending through the stator; and a sensor positioned in alignment
with the first aperture sensing a temperature of at least a surface
of the rotor.
2. The apparatus of claim 1, wherein the first aperture defines a
step aperture extending through the stator.
3. The apparatus of claim 2, further including a second aperture or
opening extending through a housing supporting the sensor, wherein
a diameter of the first aperture is smaller than a diameter of the
second aperture.
4. The apparatus of claim 2, further including a stator surface
visible to the sensor through the second aperture.
5. The apparatus of claim 2, wherein the first aperture is
coaxially aligned with the second aperture and in a line-of-sight
with the sensor.
6. The apparatus of claim 1, further including an air gap between a
lens of the sensor and the rotor, the air gap minimizing a heat
transfer to the sensor from the rotor and providing a non-contact
rotor temperature measurement in the air gap.
7. The apparatus of claim 6, wherein the air gap is further located
between a housing supporting the sensor and the surface of the
rotor.
8. The apparatus of claim 6, further including a stator surface
wherein the air gap is further provided between the lens of the
sensor and the stator surface.
9. The apparatus of claim 1, wherein the stator includes multiple
teeth, with the first aperture extending through at least one of
the multiple teeth.
10. The apparatus of claim 1, wherein the sensor defines an
infrared detector.
11. A method for automobile vehicle rotor temperature measurement
for a motor, comprising: positioning a rotor of the motor within a
stator of the motor; creating a first aperture or opening extending
through the stator; aligning a sensor with the first aperture; and
operating the sensor to sense a temperature of at least a surface
of the rotor.
12. The method of claim 11, further including shaping the first
aperture as a step aperture extending through the stator and
further including a second aperture or opening extending through a
housing supporting the sensor, with a stator surface visible to the
sensor through the second aperture.
13. The method of claim 12, further including selecting the sensor
as an infrared detector sensing the surface of the rotor and the
stator surface.
14. The method of claim 11, further including extending the
aperture through at least one of multiple teeth of the stator.
15. The method of claim 11, further including receiving a total
radiation W.sub.tot by the sensor equal to [an emission of
surroundings reflected by a target defining the surface of the
rotor]+[an emission of the target]+[an absorption through an
atmosphere and external optics].
16. The method of claim 11, further including: assuming an initial
reflected sensed temperature T_refl_initial of the surface of the
rotor to be equal to a motor oil temperature T.sub.oil of the motor
or a stator temperature if the motor oil as a coolant oil is not
available; and calculating a reflected temperature T.sub.refl which
is equal to a constant C.sub.refl multiplied by [a rotor
temperature T.sub.rotor plus a stator temperature T.sub.stator]
divided by two.
17. The method of claim 16, further including: substituting the
reflected temperature T.sub.refl for the initial reflected sensed
temperature T_refl_initial of the surface of the rotor; and
performing at least a second iteration of the calculating the
reflected temperature T.sub.refl.
18. A method for automobile vehicle rotor temperature measurement
of a motor, comprising: positioning a rotor of the motor within a
stator of the motor; aligning an infrared sensor with a surface of
the rotor; in an obtaining step obtaining multiple items from
vehicle sensor data including a motor oil temperature T.sub.oil; an
infrared sensor stator temperature signal IR_stator_raw, an
infrared sensor rotor signal IR_rotor_raw, an object emissivity
.epsilon._obj of the rotor, a predetermined transmission rate
.tau._atm, an atmospheric temperature T_atm, and a temperature at
the sensor T_optic, wherein an initial reflected sensed temperature
T_refl_initial is assumed to be equal to the motor oil temperature
T.sub.oil of the motor; performing a first temperature calibration
if the motor oil temperature T.sub.oil is less than 40.degree. C.
or a second temperature calibration if the motor oil temperature
T.sub.oil is equal to or greater than 40.degree. C.; and
calculating a value of a reflected temperature T.sub.refl which is
equal to a constant C.sub.refl multiplied by [a rotor temperature
T.sub.rotor plus a stator temperature T.sub.stator] divided by
two.
19. The method of claim 18, further including performing at least a
second iteration after determining the reflected temperature
T.sub.refl by returning to the obtaining step and replacing the
initial reflected sensed temperature T_refl_initial initially
assumed to be equal to the motor oil temperature T.sub.oil of the
motor with the value of the reflected temperature T.sub.refl.
20. The method of claim 18, further including extending a
step-aperture in a stator lamination defining an infrared radiation
pathway from the infrared sensor to enable simultaneous infrared
sensing on the surface of the rotor and on a surface of the stator.
Description
INTRODUCTION
[0001] The present disclosure relates to measurement of electric
motor rotor temperature during operation of the motor.
[0002] Electrical motors such as those used for propulsion of
electrical vehicles including hybrid electric vehicles require
accurate measurement of motor temperatures during operation to
provide optimum motor performance, to avoid inducing thermal
overprotection which could limit performance and to maximize motor
life expectancy. The rotor is the most important element to track
for temperature conditions during operation, however known
techniques to measure motor temperature during operation do not
provide for direct temperature measurement of the rotor surface
area in the air gap due to inaccessibility of the rotor.
[0003] Production motors at present rely on thermal resistance
network-based temperature estimators to provide input data to
vehicle controllers. Known temperature measurement network-based
temperature estimators include a back-EMF method which indirectly
estimates a rotor magnet overall temperature for permanent magnet
motors. A substantial drawback of the back-EMF method is this
method requires power input to the motor to be stopped for a
predetermined period of time, which is undesirable. Induction
motors do not include permanent magnets in the rotor and at present
a suitable method to measure rotor temperature is not
available.
[0004] Thus, while current motor temperature measurement systems
achieve their intended purpose, there is a need for a new and
improved system and method for measurement of electric motor rotor
temperature during operation of the motor.
SUMMARY
[0005] According to several aspects, an apparatus for automobile
vehicle rotor temperature measurement includes a motor having a
rotor. A stator is further included with the rotor positioned
within the stator. A first aperture or opening extends through the
stator. A sensor is positioned in alignment with the first aperture
sensing a temperature of at least a surface of the rotor in a
line-of-sight with the sensor.
[0006] In another aspect of the present disclosure, the first
aperture defines a step aperture extending through the stator.
[0007] In another aspect of the present disclosure, a second
aperture or opening extends through a housing supporting the
sensor, with a diameter of the first aperture is smaller than a
diameter of the second aperture.
[0008] In another aspect of the present disclosure, a stator
surface is visible to the sensor through the second aperture.
[0009] In another aspect of the present disclosure, the first
aperture is coaxially aligned with the second aperture and in a
line-of-sight with the sensor.
[0010] In another aspect of the present disclosure, an air gap is
created between a lens of the sensor and the rotor surface, the air
gap minimizing heat transfer to the sensor from the rotor and
providing a non-contact rotor temperature measurement in the air
gap.
[0011] In another aspect of the present disclosure, the air gap is
further located between a housing supporting the sensor and the
surface of the rotor.
[0012] In another aspect of the present disclosure, the air gap is
further provided between the lens of the sensor and the stator
surface.
[0013] In another aspect of the present disclosure, the stator
includes multiple teeth, with the aperture extending through at
least one of the multiple teeth.
[0014] In another aspect of the present disclosure, the sensor can
be an infrared detector.
[0015] According to several aspects, a method for automobile
vehicle rotor temperature measurement for a motor having a rotor,
includes: positioning the rotor within the stator; creating a first
aperture or opening extending through the stator; aligning a sensor
with the first aperture; and operating the sensor to sense a
temperature of at least a surface of the rotor.
[0016] In another aspect of the present disclosure, the method
further includes shaping the first aperture as a step aperture
extending through the stator and including a second aperture or
opening extending through a housing supporting the sensor, with a
stator surface visible to the sensor through the second
aperture.
[0017] In another aspect of the present disclosure, according to
one example the method further includes selecting the sensor as an
infrared detector sensing the surface of the rotor and the stator
surface.
[0018] In another aspect of the present disclosure, the method
further includes extending the aperture through at least one of
multiple teeth of the stator.
[0019] In another aspect of the present disclosure, the method
further includes receiving a total radiation W.sub.tot by the
sensor equal to [an emission of surroundings reflected by a target
defining the surface of the rotor]+[an emission of the target]+[an
absorption through the atmosphere and external optics].
[0020] In another aspect of the present disclosure, the method
further includes: assuming an initial reflected sensed temperature
T_refl_initial of the rotor surface to be equal to a motor oil
temperature T.sub.oil of the motor, or a stator temperature if a
motor oil as a coolant oil is not used; and calculating a reflected
temperature T.sub.refl which is equal to a constant C.sub.refl
multiplied by [a rotor temperature T.sub.rotor plus a stator
temperature T.sub.stator] divided by two.
[0021] In another aspect of the present disclosure, the method
further includes: substituting the calculated reflected temperature
T.sub.refl for the initial reflected sensed temperature
T_refl_initial of the rotor surface; and performing at least a
second iteration of the calculating the reflected temperature
T.sub.refl.
[0022] According to several aspects, a method for automobile
vehicle rotor temperature measurement of a motor having a rotor and
a stator, includes: aligning an infrared sensor with a surface of
the rotor; in an obtaining step obtaining multiple items from
vehicle sensor data including a motor oil temperature T.sub.oil or
a stator temperature if coolant oil is not used, an infrared sensor
stator temperature signal IR_stator_raw, an infrared sensor rotor
signal IR_rotor_raw, an object emissivity .epsilon._obj of the
rotor, a predetermined transmission rate .tau._atm, an atmospheric
temperature T_atm, and a temperature at the sensor T_optic, wherein
an initial reflected sensed temperature T_refl_initial is assumed
to be equal to the motor oil temperature T.sub.oil of the motor;
performing a first temperature calibration if the motor oil
temperature 54 T.sub.oil is less than 40.degree. C. or a second
temperature calibration if the motor oil temperature 54 T.sub.oil
is equal to or greater than than 40.degree. C; and calculating a
value of a reflected temperature T.sub.refl which is equal to a
constant C.sub.refl multiplied by [a rotor temperature T.sub.rotor
plus a stator temperature T.sub.stator] divided by two.
[0023] In another aspect of the present disclosure, the method
further includes performing at least a second iteration following
completion of the calculation of the reflected temperature
T.sub.refl by returning to the obtaining step and replacing the
initial reflected sensed temperature T_refl_initial initially
assumed to be equal to the motor oil temperature T.sub.oil of the
motor with the calculated value of T.sub.refl.
[0024] In another aspect of the present disclosure, the method
further includes extending a step-aperture in a stator lamination
defining an infrared radiation pathway from the infrared sensor to
enable simultaneous infrared sensing on the surface of the rotor
and on a surface of the stator.
[0025] Further areas of applicability will become apparent from the
description provided herein. It should be understood that the
description and specific examples are intended for purposes of
illustration only and are not intended to limit the scope of the
present disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] The drawings described herein are for illustration purposes
only and are not intended to limit the scope of the present
disclosure in any way.
[0027] FIG. 1 is a front elevational view of a motor having an
apparatus and method for rotor temperature measurement according to
an exemplary aspect;
[0028] FIG. 2 is a cross-sectional end elevational view taken at
section 2 of FIG. 1;
[0029] FIG. 3 is a flow diagram presenting steps for performing the
method of the present disclosure; and
[0030] FIG. 4 is a front elevational view of a motor having first
and second sensors of the present disclosure.
DETAILED DESCRIPTION
[0031] The following description is merely exemplary in nature and
is not intended to limit the present disclosure, application, or
uses.
[0032] Referring to FIG. 1, an apparatus and method for rotor
temperature measurement 10 according to several aspects includes a
motor 12 having rotor 14 for rotating an output shaft 16 with
respect to a shaft axis of rotation 18. The rotor 14 is positioned
within a stator 20. To accurately and directly determine a rotor
temperature T.sub.rotor at a rotor surface 22 a first through
aperture 24 is created through the stator 20. The first through
aperture 24 provides a line-of-sight access to the rotor surface
22. To accurately and directly determine a stator temperature
T.sub.stator a second through aperture 26 is created through a
housing 28 which supports the stator 20. According to several
aspects, the first through aperture 24 and the second through
aperture 26 are coaxially aligned on a common axis 30. The second
through aperture 26 provides a line-of-sight access to a stator
surface 32. To determine the rotor temperature T.sub.rotor at the
rotor surface 22 and the stator temperature T.sub.stator at the
stator surface 32 a sensor 34 such as an infrared sensor is mounted
using a sensor mount 36 to the housing 28.
[0033] Referring to FIG. 2 and again to FIG. 1, the stator 20
includes multiple stator laminations 38 individually having an
outer ring 40 and multiple inwardly extending lamination teeth 42.
Multiple stator slots 44 are provided individually positioned
between successive ones of the lamination teeth 42. Stator windings
46 made for example of copper wire are positioned within the stator
slots 44. The first through aperture 24 is created for example by
boring centrally through an exemplary one of the lamination teeth
42'. According to several aspects a first diameter of the first
through aperture 24 is smaller than a second diameter of the second
through aperture 26 which provides the line-of-sight access to the
rotor surface 22 and the line-of-sight access to stator surface 32
by the sensor 34. According to several aspects the first diameter
of the first through aperture 24 may range from approximately 1.0
mm to approximately 1.5 mm.
[0034] Referring to FIG. 3 and again to FIG. 2, a flow diagram 48
presents method steps for use of the apparatus and method for rotor
temperature measurement 10. Following a start step 50, in an
obtaining step 52, multiple items are obtained from vehicle sensor
data. These include a motor oil temperature T.sub.oil; an infrared
sensor stator temperature signal IR_stator_raw and an infrared
sensor rotor signal IR_rotor_raw. This is followed by obtaining an
object emissivity .epsilon._obj of the rotor 14, identifying a
predetermined transmission rate .tau._atm, an atmospheric
temperature T_atm, and a temperature at the infrared sensor
T_optic. An initial reflected sensed temperature T_refl_initial is
assumed to be equal to the motor oil temperature T.sub.oil of the
motor 12.
[0035] Following the obtaining step 52 if a motor oil temperature
54 T.sub.oil is less than 40.degree. C. multiple independent
temperature calibration steps may be performed. These include in a
first temperature calibration step 56 applying a temperature
calibration range 1 having a temperature ranging from -30.degree.
C. to 55.degree. C. Following the first temperature calibration
step 56 if an initial reflected temperature 58
T.sub.IR<40.degree. C. the program moves to an equation
application step 60.
[0036] Following the first temperature calibration step 56 if an
initial reflected temperature 61 T.sub.IR>=40.degree. C. the
program moves to a second temperature calibration step 62. In the
second temperature calibration step 62, because the T.sub.IR
temperature is greater than or equal to 40.degree. C. a temperature
calibration range 2 ranging from 35.degree. C. to 150.degree. C. is
applied. Following the second temperature calibration step 62 if
the initial reflected temperature T.sub.IR<140.degree. C. the
program moves directly to the equation application step 60.
[0037] Following the first temperature calibration step 56 if an
initial reflected temperature 66 T.sub.IR>=140.degree. C. the
program moves to a third temperature calibration step 68. In the
third temperature calibration step 68, because the T.sub.IR
temperature is greater than or equal to 140.degree. C. a
temperature calibration range 3 ranging from 80.degree. C. to
220.degree. C. is applied. Following the third temperature
calibration step 68 the program moves directly to the equation
application step 60.
[0038] During the equation application step 60, a below defined
Equation 1 is applied to obtain an initial rotor temperature
T_rotor_initial and a stator temperature T_stator.
[0039] In parallel temperature calibration steps, following the
obtaining step 52 if the oil temperature T.sub.oil 70 is greater
than or equal to 40.degree. C., in a fourth temperature calibration
step 72 the above noted temperature calibration range 2 of
35.degree. C. to 150.degree. C. is applied. During the fourth
temperature calibration step 72, if an initial reflected
temperature 76 T.sub.IR<140.degree. C. the program moves
directly to the equation application step 60.
[0040] Following the fourth temperature calibration step 72 if an
initial reflected temperature 76 T.sub.IR>=140.degree. C. the
program moves to a fifth temperature calibration step 78. In the
fifth temperature calibration step 78, because the initial
reflected temperature 76 T.sub.IR is greater than or equal to
140.degree. C. the above noted temperature calibration range 3
ranging from 80.degree. C. to 220.degree. C. is applied. Following
the fifth temperature calibration step 78 the program moves
directly to the equation application step 60.
[0041] The rotor surface emission and reflection calibration
increases rotor temperature measurement accuracy without increasing
emissivity (e.g., painting on the rotor surface). The rotor surface
emission and reflection calibration applied in the equation
application step 60 involves solving Equation 1 below to determine
a rotor temperature (T.sub.rotor) as a reflected temperature
T.sub.refl.
W.sub.tot=(1-.epsilon..sub.obj).tau..sub.atm.sigma.(T.sub.refl).sup.4+.e-
psilon..sub.obj.tau..sub.atm.sigma.(T.sub.obj).sup.4+(1-.tau..sub.atm).sig-
ma.(T.sub.atm).sup.4 Equation 1:
[0042] In Equation 1 above, a total radiation W.sub.tot received by
the sensor 34 is equal to multiple items including [an emission of
surroundings reflected by a target defining at least the surface of
the rotor]+[an emission of the target]+[an absorption through the
atmosphere and external optics]. In Equation 1, the
.epsilon..sub.obj is a predetermined emissivity based on an RPM of
the rotor 14. In Equation 1, the T.sub.atm is a predetermined
transmission rate.
[0043] Following the equation application step 60 in a temperature
reflected determination step 80 the temperature reflected
T.sub.refl from Equation 1 above is determined using an Equation 2
as follows:
T.sub.refl=C.sub.refl.times.[(T.sub.rotor+T.sub.stator)/2] Equation
2:
[0044] Equation 2 is formulated by determining an averaged emission
of the stator reflected by the rotor surface 22 through the first
through aperture 24. According to several aspects, the reflector
constant C.sub.refl applied in Equation 2 may be 0.85. According to
other aspects, the reflector constant (C.sub.refl) may be a value
other than 0.85 which is dependent on the first through aperture
diameter selected and a location of the first through aperture
24.
[0045] With continuing reference to FIG. 3, following completion of
the temperature reflected determination step 80 the program returns
to the obtaining step 52 but replaces the initial reflected sensed
temperature T_refl_initial which was assumed to be equal to the
motor oil temperature T.sub.oil of the motor 12 with the calculated
value of T.sub.refl identified using Equation 2 in the temperature
reflected determination step 80. At least a second iteration of the
program using the flow diagram 48 is then completed. A second
iteration complete signal 84 is then generated after which in a
forwarding step 86 values of the rotor temperature T_rotor and the
stator temperature T_stator are forwarded to a vehicle controller
88. The vehicle controller may include a motor heat generation
model 90, a heat transfer model 92 and a coolant flow model 94,
which collectively provide input to generator a motor temperature
96.
[0046] Referring to FIG. 4 and again to FIGS. 1 through 3, a
validation 98 may be performed using output signals from the sensor
34, which are compared to signals that can be received from a
second sensor 100, which may also be an infrared detector. A third
aperture 102 may be created in a housing portion 104 which permits
temperature measurement of an outer surface 106 of the rotor 14,
used to confirm agreement with the temperature measurements
received from the sensor 34. The use of the second sensor 100 may
be solely as a confirmation or may be used as a redundant component
together with the sensor 34.
[0047] With continuing reference to FIG. 4 and again to FIG. 1, an
air gap 120 is present between the lens 114 of the sensor 134 and
the housing 28 and the rotor surface 22 and between the lens 114 of
the sensor 134 and the stator surface 32. The air gap 120 minimizes
heat transfer to the sensor 34 and thereby provides a non-contact
mid-rotor temperature measurement in the air gap using the infrared
thermal detector or sensor 34.
[0048] A step-aperture defined by a combination of the first
through aperture 24 and the second through aperture 26 is made in
one of multiple stator laminations 38 defining an infrared
radiation pathway to enable simultaneous infrared sensing on both
the rotor surface 22 and the stator surface 32. The first through
aperture 24 extends through a stator lamination tooth 42 between
stator windings 46.
[0049] The rotor temperature measurement location is on the rotor
surface 22 in the air gap 120. The present rotor surface emission
and reflection calibration method increases temperature measurement
accuracy compared to known temperature estimation algorithms.
[0050] An apparatus and method for rotor temperature measurement 10
of the present disclosure offers several advantages. These include
a methodology that enables non-contact mid-rotor temperature
measurement in an air gap using a sensor such as an infrared
thermal detector. The methodology also includes a rotor surface
emission and reflection calibration method to increase measurement
accuracy. The methodology further includes a step-aperture created
in a stator lamination defining an infrared radiation pathway which
enables simultaneous infrared sensing on a surface of the rotor and
on a surface of the stator. The through aperture extends through a
stator lamination tooth between copper windings. The rotor
temperature measurement location is at the rotor surface in the air
gap.
[0051] The description of the present disclosure is merely
exemplary in nature and variations that do not depart from the gist
of the present disclosure are intended to be within the scope of
the present disclosure. Such variations are not to be regarded as a
departure from the spirit and scope of the present disclosure.
* * * * *